The presence of mitral annular calcification (MAC) confers worse periprocedural outcomes that last beyond 30 days, but transcatheter mitral valve implantation (TMVI) appears to improve technical and clinical outcomes compared to other transcatheter-based techniques, according to late-breaking trial results presented Wednesday at Transcatheter Valve Therapies (TVT) 2021.
Traditionally, patients with moderate to severe MAC are considered poor candidates for mitral valve surgery or interventions. The current data on the outcomes of TMVI are limited in these patients.
Walid Ben Ali, MD, PhD, presented 1-year outcomes of the CHOICE-MI MAC study at TVT conference at Miami Beach, Florida.
The investigator-initiated CHOICE-MI registry is enrolling patients screened for TMVI in 26 centers worldwide.
The study compared the clinical features, procedural and clinical outcomes of patients with moderate to severe MAC (MAC group) to patients with mild or less MAC (non-MAC group), irrespective of the final treatment decision.
The primary outcome was all-cause death or heart failure (HF) rehospitalization at 1 year. The secondary outcome was all cause and cardiovascular (CV) mortality at 1 year, residual mitral regurgitation (MR) and New York Functional Class (NYHA FC) assessment at discharge and 1-year, respectively.
The cohort included 668 patients (156 MAC and 512 non-MAC), and there were several significant differences between the two patient groups. The MAC group was older (mean age MAC 80 years vs. 78 years non-MAC; p=0.003), had a higher percentage of women (MAC 62.8% vs. non-MAC 40.8%; p=0.001), a higher Society of Thoracic Surgeons Predicted Risk of Mortality score (MAC 6.6% vs. non-MAC 4.8%; p=0.028), and a higher rate of previous transcatheter aortic valve replacement (TAVR; MAC 25.2% vs. non-MAC 7.2%; p=0.001). Most of the patients (MAC 82.4%, non-MAC 81.4%) had NYHA-FC III/IV symptoms.
The MAC patients also had higher average ejection fraction (MAC 58% vs. non-MAC 47%; p=0.001), lower left ventricular end diastolic volume (MAC 114.9 ml vs. non-MAC 136 ml), a lower rate of secondary MR (MAC 15.8% vs. non-MAC 47.3%; p=0.001)) a higher mean mitral valve gradient (MAC 5 mmHg vs. non-MAC 2.3 mmHg, p=0.001) and smaller mean inter-commissural diameter (MAC 38.2 mm vs. non-MAC 41.1 mm; p=0.019) and systolic mitral annular perimeter (MAC 121.1 mm vs. non-MAC 131.4 mm; p=0.047).
No procedural mortality was observed in MAC patients treated with TMVI, while the rate was 2.2% (four patients) in the non-MAC group, but this difference was not statistically significant (p=0.98). The TMVI procedure was performed predominantly via transapical access in 88% of patients, with technical success rate of more than 95%. There was numerically higher left ventricular outflow tract obstruction (7.4% vs 2.8%) and valve migration (7.4% vs. 1.1%) in MAC patients, but these differences were not statistically significant. Access-site complication was higher in the MAC group (22.2% vs 6.7%; p=0.021).
The technical success of transcatheter edge-to-edge repair (TEER) was significantly lower in MAC patients (74.1% vs 89.9%; p=0.05), and the need of more than one clip was higher in non-MAC patients (18.5% vs 50%; p=0.005). The procedural outcomes of the surgical arm were comparable between the MAC and non-MAC groups, with no difference in mitral valve repair and procedural mortality.
The primary outcome of all-cause mortality or HF hospitalization was not different between the groups (MAC 49% vs. non-MAC 34%; p=0.14). However, a landmark analysis at 1 month did show a significantly higher rate of the primary outcome at 1 year in MAC patients (45% vs. 26.4%, p=0.032). All-cause mortality alone at 1 year was numerically, but not significantly, higher in the MAC group (MAC 31.6% vs. non-MAC 21.4%; p=0.22), and this was also true with a 1-month landmark analysis (MAC 26.1% vs. non-MAC 14.4%; p=0.08). CV mortality was also higher in MAC group (18.9% vs. 14.1%) but not statistically significant.
The residual MR was not different between MAC and non-MAC patients at discharge and 1-year. However, the TMVI subgroup had more resolution of MR, with more than 70% of patients having none or trace MR at 1 year. The mitral valve mean gradient was higher in the MAC group, especially in patients treated via transcatheter. There was no significant difference in NYHA FC between the MAC and non-MAC groups, but the TMVI subgroup showed more improvement comparted to TEER and surgical patients.